Guessing from the number of posts by that user that are all very basic, the person is not in microbiology. No you do not need to heat it till it becomes red. A short duration ~1 second to be absolutely certain will suffice. The microbes are killed rapidly by the quick change from cold to hot to relative cold. The shock kills them. Kinda like taking a human to volcanic lava and then to the Greenland ice shelf.
Good practice in my microbio lab is to leave it until red. Particularly useful if you have clumps that are attached, a simple heating will not kill all bacteria. And I ‘d rather do a bit of overkill, than having to redo an experiment… Just saying.